1. Field of the Invention
The present invention relates to a resin-seal apparatus for a semiconductor element and, more particularly, to a resin-seal apparatus for a semiconductor element capable of improving productivity of a resin-sealing step for a semiconductor element.
2. Description of the Related Art
It is well-known that a resin-sealing step is performed by a transfer molding method to protect a semiconductor element from an external atmosphere. An apparatus for a special purpose is utilized in the resin-sealing step. In this apparatus, a pre-melted tablet-like sealing resin is used.
The above apparatus has a chase molding die set in accordance with a change in recent production methods for a semiconductor element from production for a small number of types of semiconductor elements to production for a large number of types of semiconductor elements.
In the above apparatus, a pot is heated by a heat-plate molding die set (to be described later) to melt the tablet-like sealing resin, and the sealing resin flows through a cull, a runner, a gate, and a cavity. After semiconductor elements to be molded which are coated with the sealing resin, a resin-sealing step is completed, and the resin-sealed semiconductor elements are released from the cavity formed by cavity blocks, thereby completing the entire steps. A resin-seal apparatus having the cavity blocks will be described below with reference to FIGS. 1A and 1B. FIG. 1A is a plan view showing the resin-seal apparatus, and FIG. 1B is a sectional view showing a main part of the resin-seal apparatus. That is, as shown in FIGS. 1A and 1B, a pair of cavity blocks 2 and 3 for mounting molded bodies, i.e., resin-sealed semiconductor elements 1 (FIG. 1A), are sandwiched by chase bodies 4 and 5, and lower and upper ejector plates 6 and 7 are arranged to sandwich the chase bodies 4 and 5. In addition, a plurality of ejector pins 8 and a plurality of support pins 9 are arranged between the ejector plate 7 and the cavity block 2 and between the ejector plate 6 and the cavity block 3. The ejector pins 8 eject the molded bodies, and the support pins 9 apply a uniform clamping pressure on the semiconductor elements to be molded. In addition to elastic members 10, screws 11 and sleeves for preventing the chase bodies 4 and 5 and the ejector plates 6 and 7 from dropping are arranged between the chase bodies 4 and 5 and the ejector plates 6 and 7.
In the apparatus having the above arrangement, although the support pins are arranged for applying a uniform pressure on the cavity blocks, since the elastic members 10 for pushing up the ejector pins are arranged, it is difficult that the support pins are freely arranged with good balance. Therefore, a uniform pressure does not act on the cavity blocks, and resin leaks from the cavity to produce resin flashes. In addition, when the cavity blocks and the ejector pins are not easily operated due to contact therebetween, the resin-sealed semiconductor element cannot be pushed down to the lower cavity block by a force of the spring, and the resin-sealed semiconductor elements cannot be easily released from the cavity. Furthermore, when small-size cavity blocks are used, no uniform pressure acts on the cavity blocks. For this reason, the cavity blocks are deformed by a clamping pressure generated during the molding operation to cause the resin to leak from the cavity so as to produce resin flashes, and excellent molded bodies cannot be obtained. In addition, since the structure of the heat-plate molding die sets is complicated, a low-price and small-size apparatus cannot be obtained.